Planar electrical contacts of the fork type are well known as are connectors that use such contacts. A typical prior fork contact is shown in U.S. Pat. No. 4,030,799. Such fork contact has a pair of tines that extend out from a base. A member, such as a pin contact, may be inserted between a pair of tines to make an electrical connection therewith. Such patent also discloses an electrical connector using such contacts. The connector is of the cable termination assembly type, which includes the contacts, a housing, and at least a portion of a multiconductor cable. The present invention may be used with such cable termination assemblies and with other types of electrical connectors, such as a cable termination, which is like the noted assembly but without necessarily including the cable as a part thereof.
It is well known that such fork contacts may be formed by die cutting or die stamping the same from a relatively thin sheet of metal material. However, such stamping often leaves the finished product with a smooth side, which is the one that the cutting die strikes first, and a burr side or surface. The sharp, rough burrs at such burr side usually are undesirable because they can damage pin contacts inserted to engagement therewith, for example by scoring off high conductivity coatings or the like applied to such pin contacts. It would be desirable to permit such die cutting of fork contacts while eliminating with facility such scoring and like problems created by such burrs.
To improve the electrical conductivity and possibly for other reasons electrical contacts often are plated with certain materials, such as high conductivity materials. For example, a contact formed of nickel silver may be plated with gold or palladium silver in order substantially to improve the electrical conductivity thereof, especially at the surface area of the contact where it engages with or wipes against a pin contact or other member inserted to engage the same. Plating materials, though, sometimes are applied non-uniformly, which may result in uneven wear; and there may be voids in the plating allowing undesirable oxidation to occur. Also, plating is unnecessarily relatively expensive because the entire contact usually is plated, which wastes plating material at portions of the contact that do not perform a contacting function.
The use of relatively highly conductive or high conductivity inlay material has eliminated the need for plating an entire electrical contact, but contacts using inlay material usually are non-planar and relatively large in comparison to the required dimensions of a planar fork contact or the like. An advantage of inlay material over plating is the former would be denser and more uniform in thickness than the latter. Also, the inlay material usually would present a contacting surface area for engaging an inserted member, e.g. a pin contact, that is smoother and, therefore, a better contacting surface, than the plated or unplated surface, say of a conventional fork contact. The usual technique for applying inlay material to sheet material has been to force by pressure, e.g. by a rolling process, a strip of inlay material into a shallow groove in the sheet material from which the contact would be cut. Then, the contact would have to be deformed, for example in the shape of a hairpin curve or in the form of a full or three quarters folded box that has contact arms extending, say upwardly, from respective opposite sides of the box and parallel thereto, in order to locate the inlay material at a position of contacting exposure to a pin contact inserted to engagement therewith.
In contrast, though, a planar fork contact is a secure, integral device that requires minimum space while assuring a highly effective contacting/wiping function to establish a connection with, for example, a pin contact or other member inserted between the tines thereof to engagement therewith. A planar fork contact would be one that has the tines and preferably, although not necessarily, the base, which holds the tines thereto, all substantially in a single narrow plane, i.e. that plane of the sheet material from which the contact is formed, especially by the noted die cutting. It would be desirable to provide inlay material at the contacting/wiping areas of the tines of such planar fork contacts.
With the foregoing in mind, then, it would be desirable to be able to manufacture planar fork contacts that are substantially uniform, that have contacting material, such as gold inlay or the like, at the contacting areas of one and preferably both of the fork tines, and/or that provide a smooth contacting surface for engagement with pins or other members inserted to engagement with respective contacts even though the contacts are formed by a stamping or die cutting process.